Dynamic internal humidity control

ABSTRACT

Controlling internal humidity for a device by receiving an environmental parameter relating to a humidity control in the device, analyzing the environmental parameter to determine a humidity condition of the device, and sending a signal to activate a heater based on the humidity condition. A device including humidity control includes a humidity measuring arrangement, a temperature measuring arrangement, a processor receiving a humidity input from the humidity measuring arrangement and a temperature input from the temperature measuring arrangement, the processor comparing the humidity input and temperature input to stored data to determine a humidity condition of the device and a heater which is activated upon the determination of a predetermined humidity condition.

BACKGROUND

Mobile units (MU) such as mobile computers are relied on for business and personal use in a wide variety of applications. Many of these devices are used in a variety of environments where rapid changes in temperature and humidity are common. High levels of humidity may develop internally in a mobile unit which reduces the product life cycle and reliability.

Many mobile units also include optical devices. Optical devices include scanners and imagers. A rapid change in the temperature of the air within the housing of an optical device can cause condensation to build up on an optical window of the device, interfering with operation. In particular, condensation building up within the housing is a difficult problem to address. Some devices employ a chemical desiccant within the housing to remove moisture. However, chemical desiccants have a short lifetime and becomes useless when saturated. The desiccant must then be changed. Again, this is a difficult process because the desiccant is within the housing and users are generally discouraged from opening the housing because it may damage the device, void the warranty, etc.

SUMMARY OF THE INVENTION

The present invention is related to a method for humidity control. The method comprises receiving an environmental parameter relating to a humidity control in a device, analyzing the environmental parameter to determine a humidity condition of the device, and sending a signal to activate a heater based on the humidity condition.

In an exemplary embodiment of the present invention, a dual function heater within a terminal is created. One function is to warm internal components at low ambient temperatures while the other function is to remove internal humidity typically associated with higher ambient temperatures and humidity. Using hardware and/or software, the internal humidity of the mobile device may be monitored and the humidity may be dissipated using the heater. The hardware and/or software may also monitor the change of temperature and humidity and appropriately enable the heater to remove the humidity while minimizing the energy required to remove the humidity.

DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary system of a humidity controller according to the present invention.

FIG. 2 illustrates an exemplary circuit diagram of a heater control of a mobile unit according to the present invention.

FIG. 3 illustrates an exemplary method of humidity control according to the present invention.

DETAILED DESCRIPTION

The present invention may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. The exemplary embodiment of the present invention describes a system and method for a dynamic internal humidity control for a mobile device. However, those skilled in the art will understand that the exemplary humidity control may be implemented in any device, whether the device is mobile or stationary. The humidity control is performed by a humidity controller and its constituent parts. The controller and parts will be discussed in detail below.

FIG. 1 illustrates an exemplary system 200 of a humidity controller 201 according to the present invention. The humidity controller 201 measures an actual amount of humidity and an ambient temperature (i.e., environmental parameters) during the use of the humidity controller 201 to predict and control humidity within the device. The humidity controller 201 maintains a preset atmospheric condition in order to prevent the humidity level to go beyond a certain predetermined value, thereby preventing any damage to the unit and increasing product life cycle and reliability. Also, the humidity controller 201 maintains a preset temperature in order to prevent any condensation build up (i.e., fogging) on any glass or clear surface that may be present on the unit. The glass surface may be, for example, a transparent window for a scanner or imager or a display screen for a computing device. It should be noted that the example of the glass surface is exemplary only and that the surface may just as easily be composed of transparent plastics (as is exhibited on many conventional technologies).

In the present invention, the amount of humidity is measured using a humidity detector 202. The humidity detector 202 may be, for example, a humidity or moisture meter. In a preferred embodiment of the present invention, the humidity detector 202 is placed within the unit. Placement of the humidity detector 202 within the unit allows a more direct, accurate measurement of internal humidity to assess any subsequent actions to be taken by the humidity controller 201.

The ambient temperature is measured using an ambient temperature detector 203. The ambient temperature detector 203 may be, for example, a thermocouple, a resistance temperature detector (RTD), etc. In a preferred embodiment of the present invention, the ambient temperature detector 203 is placed on the periphery of the unit. Placement of the ambient temperature detector 203 on the periphery of the unit allows a more direct, accurate measurement of ambient temperature to assess any subsequent measures to be taken by the humidity controller 201. It should be noted that a second, internal temperature detector may also be included in the present invention. The second, internal temperature detector may be used to measure the temperature within a unit. This second measurement of temperature may be used by the humidity controller to further determine the amount of control to be exerted by the humidity controller 201.

Both the humidity detector 202 and the ambient temperature detector 203 provide input to a processor 204. The processor 204 includes the logic for determining when and by how much the unit will control the conditions of the humidity controller 201. As will be described in detail below, the processor 204 may be used in conjunction with a heater control 207 to control humidity within the housing of a device. In an alternative embodiment, the processor 204 may be used to directly control a heater 208 to control humidity within the housing, i.e., the heater control 207 may be eliminated. In a further exemplary embodiment, the processor 204 may not be used. For example, an additional hardware circuit, chop (e.g., an ASIC), or specialized computing device may be used to perform the functions described herein for the processor 204. Thus, those skilled in the art will understand that while the exemplary embodiment is described with reference to a processor 204 and a heater control 207, it is possible to implement the present invention without these specific components.

In the exemplary embodiment, the processor may contain a memory 205 and an input/output component 206. The memory 205 may be used, for example, to store previously measured data by the humidity detector 202 and the ambient temperature detector 203. The memory may be a separate component outside the processor itself, e.g., hard drive, flash memory, ROM, etc. The input/output component 206 may be used, for example, to send any signals that the processor 204 generates or the received input to subsequent units involved with the dynamic humidity control. It should be noted that there may be further components connected to the processor 204 of the humidity controller 201. For example, a display mechanism may be used to indicate to a user that a component of the humidity controller 201 has been activated. The display mechanism may be, for example, a light emitting diode (LED), a speaker, or a digital display.

In order to accomplish the humidity control, a heater 208 is utilized. A heater control 207 is used to adjust the heater 208 operation by receiving signals from the input/output components 206 of the processor 204. The use of the heater 208 allows the humidity controller 201 to control the amount of humidity to be present within the unit and the temperature of any glass surface prone to condensation buildup. For example, if the ambient temperature reaches very low values, then the heater 208 may be activated to raise the temperature of the unit to a sufficient amount to prevent both high levels of humidity building up within the unit and condensation from forming on any glass surfaces.

For example, when it is very cold, the heater 208 may be used to warm the components within the device. However, when the ambient temperature is higher, it may also be advantageous to turn on the heater to prevent moisture build-up, condensation, fogging, etc., within the device. Thus, the processor 204 may store data in the memory 205 indicating certain environmental factors. In one example, the memory 205 stores dew point temperatures for various ambient humidity levels. Thus, the processor 204 receives the humidity detector 202 input and determines the dew point temperature based on the data stored in memory 205. The processor 204 also receives the ambient temperature input from ambient temperature detector 203. If the processor determines that the ambient temperature trend is dropping toward the dew point, the processor 204 may send an output signal to the heater control 207 to turn the heater 208 on to prevent the dew point from being reached inside the device, thereby preventing condensation, fogging, etc. and also minimizing the amount of energy required to maintain humidity conditions.

The above example shows that the humidity controller 201 may be used to preemptively stop humidity issues by predicting trends or other changes in environmental conditions. It also shows that the heater 208 is not limited to low temperature operation. For example, in high humidity locations, the temperature may be fairly high (e.g., 60° F.), but the heater 208 may be used to prevent the temperature inside the device from dropping a few degrees (even at the high temperature) to prevent condensation from occurring.

FIG. 2 illustrates an exemplary circuit diagram of a heater control (e.g., heater control 207) of a mobile unit implementing the humidity control according to the present invention. The following will describe the components and functionality that may be used to implement the exemplary embodiment of the heater control 207. It will not describe every component since those skilled in the art will understand the purpose and functionality of the components used to control the heater 208.

Initially, the heater control 207 includes a component U30 which is, for example, a MAX6510CAUT-T that is a resistor-programmable SOT (small outline transistor) temperature switch sold by Maxim Integrated Products. The component U30 operates as a thermostat to enable the heater 208. Thus, the output of pin 3 is used to control the heater 208. Those skilled in the art will understand that the output of pin 3 and the components which are downstream of the output enable/disable the heater 208 which is connected to heater control 207 via heater connection CN15.

The resistor R208 may be used to set a set point for heater operation. For example, the resistor R208 may set a set point for low temperature heater operation (e.g., if temperature is below 0° C., turn on heater). However, the resistor R534 allows the terminal to incorporate multiple temperature values to turn on the heater 208. The resistor R534 in conjunction with MOSFET Q66 allows the processor 204 to enable the heater 208 at a high temperature typically set when high humidity is expected. As described above, the heater 208 may be used at higher temperature than expected for heater operation because the heater 208 is being used for both heating of components at low temperatures, but also for humidity control at higher temperatures. The resistor R534 may be, for example, a discrete resistor. However, it should be noted that the resistor R534 being a discrete resistor is exemplary only and that other resistor types may be used. For example, the resistor R534 may be a variable or processor controlled resistor which would allow a dynamic enablement of the heater as different ambient conditions exist.

It should be noted that the use of the thermostat component U30 is exemplary only and that the present invention may be implemented without the use of that component. For example, the processor 204 may directly enable and disable the heater 208 as a result of the processor 204 directly monitoring the humidity detector 202 and the ambient temperature detector 203.

FIG. 3 illustrates an exemplary method 400 of humidity control according to the present invention. Initially, in step 401, the humidity controller 201 is activated. The humidity controller 201 may be activated personally by the user or it may be automatically activated upon activation of the mobile unit. The humidity controller 201 may also be activated using a sensor that determines if the humidity controller 201 should be activated. The sensor would be connected to a processor of the mobile unit that sends a signal to the humidity controller 201.

In step 402, the humidity and ambient temperature are measured. As discussed above, the humidity detector 202 and the ambient temperature detector 203 perform these measurements, respectively. The measurements performed may be taken dynamically throughout the use of the mobile unit. For example, the measurements may be taken continuously to ensure that the mobile unit functions efficiently without any hindrance due to a gap in measurements. The measurements may be taken based on a timer to be performed every preset time period (e.g., 10 seconds, 30 seconds, 1 minute, 5 minutes). The measurements may also be taken upon based on a change in atmosphere conditions. This change may be detected, for example, by the sensor discussed above.

The measured values are fed to the processor 204 and, in step 403, the method 400 determines if the conditions are acceptable. As discussed above, the acceptable conditions may be preset during the manufacturing of the mobile unit. The acceptable conditions may also be ascertained by using a simple algorithm that incorporates different factors such as operating temperatures of components of the mobile unit, consequences of the operation of components of the mobile unit, and resultant internal temperature.

If the measurements are found to be acceptable conditions for the mobile unit, then the method 400 returns to step 402 where a continuous process is created to dynamically control the humidity level in and around the mobile unit. It should be noted that subsequent measurements may be taken based on the above mentioned methods.

If, however, the measurements are found to be unacceptable conditions for the mobile unit, then the method 400 proceeds to step 404 where the processor 204 determines the amount of control necessary to counterbalance the unacceptable conditions. Once the processor 204 makes such a determination, the input/output component 206 sends a signal to the heater control 207. Upon sending this signal, in step 405, the heater is activated. The method 400 then returns to step 402 to create the continuous process discussed above.

It will be apparent to those skilled in the art that various modifications may be made in the present invention, without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. 

1. A method, comprising: receiving an environmental parameter relating to a humidity control in a device; analyzing the environmental parameter to determine a humidity condition of the device; and sending a signal to activate a heater based on the humidity condition.
 2. The method of claim 1, wherein the environmental parameter includes one of a humidity inside the device, a humidity in an operating location of the device, a temperature inside the device and a temperature in an operating location of the device.
 3. The method of claim 1, wherein the humidity condition is one of acceptable and unacceptable, the signal to activate the heater being sent only when the humidity condition is unacceptable.
 4. The method of claim 1, wherein the analyzing includes: comparing the environmental parameter to stored parameters.
 5. The method of claim 1, wherein the analyzing includes: determining a trend of the environmental parameter.
 6. The method of claim 1, further comprising: sending a signal to activate the heater based on a temperature condition.
 7. The method of claim 1, wherein the environmental parameter is at least two environmental parameters.
 8. A device, comprising: an environmental measuring arrangement; an analyzing component to determine a humidity condition of the device based on parameters from the environmental measuring arrangement; and a heater which is activated based on the determined humidity condition of the device.
 9. The device of claim 8, wherein the environmental measuring arrangement is one of a humidity measuring arrangement and a temperature measuring arrangement.
 10. The device of claim 8, wherein the environmental measuring arrangement is at least two environmental measuring arrangements.
 11. The device of claim 8, further comprising: a heater control receiving input from the analyzing component, the heater control controlling operation of the heater.
 12. The device of claim 8, wherein the analyzing component is a processor.
 13. The device of claim 11, wherein the heater control includes a thermostat, the thermostat including at least two set points.
 14. The device of claim 8, wherein the analyzing component includes a memory storing environmental data, the humidity condition being further based on the environmental data.
 15. The device of claim 8, wherein the heater is further activated based on a temperature condition measured by the environmental measuring arrangements.
 16. A device, comprising: a humidity measuring arrangement; a temperature measuring arrangement; a processor receiving a humidity input from the humidity measuring arrangement and a temperature input from the temperature measuring arrangement, the processor comparing the humidity input and temperature input to stored data to determine a humidity condition of the device; and a heater which is activated upon the determination of a predetermined humidity condition.
 17. The device of claim 16, wherein the processor outputs a heater activation signal when the humidity condition is the predetermined humidity condition.
 18. The device of claim 17, further comprising: a heater control receiving the heater activation signal and controlling the heater based on the heater activation signal.
 19. The device of claim 16, further comprising: a memory storing the stored data, where the stored data is environmental data.
 20. A device, comprising: at least two environmental measuring arrangements; an analyzing means to determine a humidity condition of the device based on parameters from the at least two environmental measuring arrangements; and a heating means that activates based on the determined humidity condition of the device. 